The deletion of unwanted memories is still a challenge that neurobiology cannot meet. If only it could. The imagery and accounts we’ve seen and heard since the Manchester bombing will affect us all for a long time.
Events such as this generate an ‘epicentre’ of trauma where those who were present or witnessed the immediate aftermath may suffer post-traumatic stress disorder. This is when memories generated by the events are encoded and consolidated differently from everyday memories and can lead to debilitating flashbacks. The evolutionary value of this mechanism is uncertain.
The unmediated phone footage that has been shared is unlikely to lead to PTSD itself, but seems to risk the creation of disturbing memory traces. Something about its horrifying nature has an impact on how they are stored. Pleasant memories don’t seem to recur to the same extent, but deeply traumatic ones can; the emotional shock when a memory is laid down is often re-evoked when it is recalled.
Not clicking on the more ghoulish images is the wisest course. This is not to ignore the horror. But we can try to fight it while still protecting ourselves.
Dr Daniel Glaser is director of Science Gallery at King’s College London